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Threshold Intensity (threshold + intensity)

Distribution by Scientific Domains
Medical Sciences50%

Selected Abstracts

New Insights on the Threshold Intensity for Improving Cardiorespiratory Fitness

PREVENTIVE CARDIOLOGY, Issue 3 2003
Barry A. Franklin PhD
First page of article [source]

Slow Repetitive TMS for Drug-resistant Epilepsy: Clinical and EEG Findings of a Placebo-controlled Trial

EPILEPSIA, Issue 2 2007
Roberto Cantello
Summary:,Purpose: To assess the effectiveness of slow repetitive transcranial magnetic stimulation (rTMS) as an adjunctive treatment for drug-resistant epilepsy. Methods: Forty-three patients with drug-resistant epilepsy from eight Italian Centers underwent a randomized, double-blind, sham-controlled, crossover study on the clinical and EEG effects of slow rTMS. The stimulus frequency was 0.3 Hz. One thousand stimuli per day were given at the resting motor threshold intensity for 5 consecutive days, with a round coil at the vertex. Results:"Active" rTMS was no better than placebo for seizure reduction. However, it decreased interictal EEG epileptiform abnormalities significantly (p < 0.05) in one-third of the patients, which supports a detectable biologic effect. No correlation linked the rTMS effects on seizure frequency to syndrome or anatomic classification, seizure type, EEG changes, or resting motor threshold (an index of motor cortex excitability). Conclusions: Although the antiepileptic action was not significant (p > 0.05), the individual EEG reactivity to "active" rTMS may be encouraging for the development of more-powerful, noninvasive neuromodulatory strategies. [source]

Sign inversion of the optical torque on the nematic director enhanced by anthraquinone dye dopants stable to the light action

LASER PHYSICS LETTERS, Issue 11 2006
V. Ya.
Abstract By analyzing the total and on-axis transmittance of the laser beam we studied the enhanced light-induced director reorientation (Jánossy effect) in a nematic liquid crystal doped with anthraquinone dye molecules that do not have photoinduced conformational transformations. The obtained dependence on the angle between the light polarization E and the initial director n0 shows: first order director reorientation (DR) transition with hysteresis for E , n0; second order reversible DR transition with the extremely low threshold intensity for E , n0; sign inversion of the nonlinear refractive index and DR in the intermediate geometry. The data suggest a presence of two different kinds of dipoles in the system: those absorbing light and those giving rise to the nonlinear refractive index. (© 2006 by Astro, Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source]

The sites of neural adaptation induced by resistance training in humans

THE JOURNAL OF PHYSIOLOGY, Issue 2 2002
Timothy J. Carroll
Although it has long been supposed that resistance training causes adaptive changes in the CNS, the sites and nature of these adaptations have not previously been identified. In order to determine whether the neural adaptations to resistance training occur to a greater extent at cortical or subcortical sites in the CNS, we compared the effects of resistance training on the electromyographic (EMG) responses to transcranial magnetic (TMS) and electrical (TES) stimulation. Motor evoked potentials (MEPs) were recorded from the first dorsal interosseous muscle of 16 individuals before and after 4 weeks of resistance training for the index finger abductors (n= 8), or training involving finger abduction-adduction without external resistance (n= 8). TMS was delivered at rest at intensities from 5 % below the passive threshold to the maximal output of the stimulator. TMS and TES were also delivered at the active threshold intensity while the participants exerted torques ranging from 5 to 60 % of their maximum voluntary contraction (MVC) torque. The average latency of MEPs elicited by TES was significantly shorter than that of TMS MEPs (TES latency = 21.5 ± 1.4 ms; TMS latency = 23.4 ± 1.4 ms; P < 0.05), which indicates that the site of activation differed between the two forms of stimulation. Training resulted in a significant increase in MVC torque for the resistance-training group, but not the control group. There were no statistically significant changes in the corticospinal properties measured at rest for either group. For the active trials involving both TMS and TES, however, the slope of the relationship between MEP size and the torque exerted was significantly lower after training for the resistance-training group (P < 0.05). Thus, for a specific level of muscle activity, the magnitude of the EMG responses to both forms of transcranial stimulation were smaller following resistance training. These results suggest that resistance training changes the functional properties of spinal cord circuitry in humans, but does not substantially affect the organisation of the motor cortex. [source]